1. Field of the Invention
The present invention relates to a signal transmission device, and more particularly, to a signal transmission device disposed on a portable electronic device to conveniently connect the foresaid portable electronic device to another portable electronic device.
2. Description of the Prior Art
With the advanced technology, the smart phone not only can be utilized to communicate by voice call and to receive/transmit the text message, but also can install lots of application programs for entertainment. A built-in battery of the smart phone may be easily depleted since the high energy consumption application program is operated, such as transmitting file and playing games or videos, and a portable battery charger or a backup battery might be the essential equipment. A conventional battery charger is a soft cable, which is detachable with the smart phone. The detachable battery charger may be lost so that the smart phone cannot be charged or cannot transmit/receive the file. Therefore, development of an assembly design involved with the battery charger and the mobile phone to provide advantages of preferred aesthetic and convenient operation is an important of the mobile phone industry.